Computer cut out knobs

I know this is simple.  This is my first boat build that is a computer cut out kit.  Do you plane down the little knobs on the cut outs?

Thanks, KorKoro

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RE: Computer cut out knobs

SOME, yes.

What's important is WHICH of those little tabs or 'knobs' as you call 'em.

Take a close look at your parts. The tabs / knobs that are FULL THICKNESS PLYWOOD ought to be left as-is. Those serve to hold pieces in their proper alignment when they're inserted into holes milled into the adjoining parts such as hull panels (strakes) and bulkheads.

The leftover bits from CNC machine-cutting of parts (left there when the machine's doing its thing so that parts that would otherwise be entirely free to move if cut full thickness on 100% of their edges CAN'T move; they're called registration tabs, for lack of a better term) are typically maybe half-thickness ply.

If you have doubts which is which, you ought to be able to tell the difference once you start assembling your kit. The tabs that hold pieces in proper position will have corresponding holes cut into the panels they're meant to be mated to.

The vestigal 'registration' tabs will be in the way as there's no holes for 'em to fit into. They served their purpose when the sheets of ply were turned into boat parts! It's up to you to remove the stuff that no longer's there to fulfill a practical purpose before you can fit your kit parts into what looks like a boat.

I'll use a sharp block plane to remove those vestigal tabs, or a SHINTO rasp if a plane's not doing a proper job of it. You could use a box cutter too if you're careful and it has a sharp blade fitted but watch your fingers! Once you've removed 90% of the tabs you can carefully finish the edge so it blends into the part's outline with a sanding block and some 100 grit sandpaper.


RE: Computer cut out knobs

If my last post leaves you puzzled as to what exactly I'm referring to, take a look at a thread running here: where another forum member's posted pics that clearly show the CNC-machine artifacts that must be removed from CNC-cut kit panels before assembly.

Usually – but not always – they look like the tiny tabs that show in the second image included in jharr's post at 9:45 AM Sunday. There's four of 'em in that pic: three are pointing at you, the fourth pointing away.

Tabs that should be left in place are longer, more like 1/2" - 5/8" long. Those hold pieces in their proper places when you're fitting things like bulkheads to bottom and side panels.

RE: Computer cut out knobs

The description is a little hazy. A panel is the large, usually rectangular, planar component that fills the opening in the wall to obstruct it when closed and rotates on hinges to optionally allow passage through the aperture in the wall.

Check here:


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